1. Field of the Invention
The invention relates to a method of regulating fertility in swine using epostane.
2. Information Disclosure Statement
Epostane is the United States Adopted Name (1986 USAN and the USP dictionary of drug names, 1961-1985 cumulative list) for (4.alpha.,5.alpha.,17.beta.)-4,5-epoxy-3,17-dihydroxy-4,17-dimethylandrost -2-ene-2-carbonitrile having the structural formula ##STR1## and having utility as an interceptive (pregnancy disrupting) agent.
Christiansen U.S. Pat. No. 4,160,027 issued July 3, 1979 describes epostane as the product of part (f) of EXAMPLE 1, that is, 4.alpha.,5.alpha.-epoxy-17.beta.-hydroxy-4,17-dimethyl-3-oxoandrostane-2.a lpha.-carbonitrile having the structural formula ##STR2## which represents the keto form of epostane. Formula I represents the enol form. The patent shows the interceptive utility of epostane in the rat and the monkey.
The only domestic animal in which the use of epostane has been described is the sheep.
A Ledger et al. (Journal of Steroid Biochemistry, vol. 17, no. 3, p. xci, abst. 271, 1982) paper entitled THE SUCCESS OF LABOUR INDUCED BY PROGESTERONE WITHDRAWAL IN PREGNANT SHEEP describes the use of epostane "to induce labour in sheep during late pregnancy".
The master of science in animal science degree thesis of Jeffrey A. Blackwell (New Mexicon State University, Las Cruces, N. Mex., 1984) entitled REPRODUCTIVE PERFORMANCE OF EWES TREATED WITH AN INHIBITOR OF PROGESTERONE SYNTHESIS describes the effects of epostane medication at day 10 of the estrus cycle in cycling ewes, specifically, serum progesterone levels, recycling time, conception rate and number of lambs produced.
A second Ledger et al. paper (Journal of Endocrinology, vol. 105, pp. 227-233, 1985) describes the "effects of an inhibitor of 3.beta.-hydroxysteroid dehydrogenase (epostane) on uterine activity and cervical softening . . . in eight sheep during late pregnancy".
The Arthur Walpole Memorial Lecture for the Society for the Study of Fertility by Robert Webb (University of Aberdeen, 1985) describes the effects of epostane on ovulation rate and production of lambs in ewes.